Shape memory behavior of high strength Ni54Ti46 alloys

Shape memory behavior of highly Ni-rich Ni54Ti46 alloys was studied after aging (550 °C, 3 h, furnace cooling). A sequence of phase transformations was observed and the shape memory behavior is found to be highly stress dependent. After aging, a transformation strain of 1% with low temperature hysteresis is observed under an ultra high stress level of 1500 MPa in compression. Moreover, superelastic response with 3% total strain can be obtained even when high stress level of 1500 MPa is applied.